All relay telephone line circuit and line finder



June 7, 1949. R. w. JONES 2,472,428

ALL RELAY TELEPHONE LINE CIRCUIT AND LINE FINDER Filed July 22, 1947 s sheets-sheet 1 common LnsT plgT INVENTOR. ROY W JONES ATTORNEY June 7, 1949. w, JONES 2,472,428

ALL RELAY TELEPHONE LINE CIRCUIT AND LINE FINDER Filed July 22, 1947 S- Sheets-Sheet 2 .a SAME FINDER 28\ I 29 254 4... X'f-fi I ass m- 21s 228 25 v 236 INVENTOR.

ROY W. JONES ATTORNEY ALL RELAY TELEPHONE LINE CIRCUIT AND LINE FINDER Filed July 22, 1947 R. W. JONES June 7, 1949.

3 Sheets-Sheet 5 FIG.3

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INVENTOR. ROY W. JONE$ ATTOR NEY Patented June 7, 1949 pr, nanny TELEPHONE LINE CIRCUIT AN LI I DE Roy W. Jone R hest ass gnor t Auto: mat Electric abor to es Inc; hica o, il -i e to -r tation o Dela e Application July 22, 1947, Serial No, 762,751

(01. mars) cl m 1 The present invention relates in general to amtomatic telephone systems, and more particularly to improvements in automatic switching apparatus adapted for use in all-relay private automatic exchanges.

The principal object of the invention is to provide an improved 'linefinder designed for use in a small private automatic exchange switchboard of the all relay type.

A further and more specific object is the pro..- vision of a simplified and economical circuit arrangement in the line equipment and call allote ter, enabling a more positive and reliable operation thereof.

A feature of the invention is the provision of improved circuits for operatingonlyone line relay at a time, such relays having one winding providing the initial operating circuit and the other winding providing the holding-circuit. The holding circuit for the line relays is a chain circuit through all of the other line relays and is so designed that a line relay can lock operated only when no other line relay is operated.

Another feature is an improved marking arrangement in whichthe marking conductors for Z:

operating the finder tens and units relays extend direct from the line relays to the finder connect relays instead of running such conductor-s through the usual tens and units guard relays .of the common relay distributor circuit.

Further features of the invention pertain to the particular arrangement of the circuit elements, whereby, the above and additional opere ating features are attained.

The novel features believed to be characteristic of the invention are set forth with particularity in the appended claims. The invention, both as to its organization and method of operation together-with further objects and advantages thereof, will best be understood :by reference to the specification taken in connection with the ace companying drawings in which:

Fig. 1 shows subscribers stations such as A, B, C and D connected to lines Lil, Llll, LM, and LED respectively. it shows a .statlons equipment such as A, more in detail and also shows the-indie yidual line equipment.

"Fig. 2 shows a call allotter'and a li-nefinder cirsuit.

Fig. 3 shows only the relays of a connector .as necessary for the proper operation .of the finder.

General description Referring to- Fig. l, the reference characters A, 33, and '19 indicate subscribers stations, with the equipment of station A being shown in de: tail. The telephone at station A s con ected with the syst m over line H m ri in confine: tors l and 2. The line .eguipment individual to each station compris s line relays, such as line relays I40, I50, I fill and Fill}, and cutofi relays, such as relays lflil, M ll, 12.0 and [:39 respectively. The line relays contain two windings, one pro-1 viding their operating circuit and the other providing their holding (gimp-it. The holding circuit for the line relays is ,a chain circuit throu h con; tacts of all the other line relays and is so designed that a line relay can lock operated only if no other line relays are operated. Fourth conductors such as L6 and 41 are provided through the linefinder to the associated connector to supply special services. Tens and units marking leads, such as tens marking conductors 23 and 2,4 and units marking conductors 121 and 22 extend from the line relays to contacts on the respective finder connect relays for controlling the operation of the finder tens and units relays.

Referring to Figs. 2 and 3, finder start relay 250 is designed to tbeloperated joy all lines having numerical designations ending in 1 through 5, and finder start relay 2t!) to be operated. by all lines having numerical designations ending in 6 through 0. It may he assumed that there are any number of finders, the exact number bein dependent on the trams and type of service re: quired. Only part .01 he last finder has been shown in detail. ThelcQnnect relays such as 289, extend the tens and units marking conductors to the finder tens and units relays. Only two of the units relay group has been shown {relays 22-0 and 2 30), Whereas, act lily five are used. Two of the tens relay group also has been shown (relays 2'00 and 2 I ll) but their exact number is dependent on the number of group vof lines to be served by the equipment. if 59 lines are served, 6 tens re: lays a need d; .whi e:.ii $3 din s a e s ved, :8 tens relays are needed. The finder is limited to s rv n t more than 0! lines. Tormv d fiezd: bility and eflicient operation, whenever the finder unit switching relay 240 of the selected finder is op ra ed, the connec on is ex ended hrou h its front contacst for a ines h}avi ng numerical (16S:-

ignations ending in fithrough 0. When the finder I or back contacts of relay 240, dependent on the last digit of the calling lines numerical designation.

Referring to Fig. 3, only the differential relay 300, the line relay 3!!! and the hold relay 320 of an associated connector link has been shown. Such a connector used in conjunction with this linefinder is of the type disclosed in the pending application of John H. Voss, Ser. No. 765,684, filed August 2, 1947.

Operation Th operation of the invention as to the origin of a call from any one of subscribers A through D, and the operation of the line equipment and linefinder as to finding the calling line will now be discussed.

Assuming that subscriber A of line LI I intends to place a call, the removal of his receiver completes a loop over his line conductors I and 2. The line relay I40 is energized through its upper winding by a circuit extending from ground through contacts I02, conductor 2, the closed loop, conductor I, contacts lI, the upper winding of relay I40, conductor 21, contacts 253 and 264 to battery. At contacts I4I, line relay I40 prepares its own locking circuit. At contacts I42, line relay I40 applies a ground potential to its incoming C conductor, thereby busying the calling line and preventing any incoming calls while the present call is being made. At contacts I43, relay I40 opens a circuit to the cut-off relay I00. At contacts I44, relay I40 prepares for the marking of the tens conductor 24. At contacts I45, relay I40 prepares for the marking of the units conductor 22. At contacts I46, relay I40 completes a circuit for energizing the finder start relay 250, this circuit extending by way of ground at contacts I46, conductor 26, the winding of relay 250 and operated contacts 212 to battery.

In operating, at X contacts 254 which close prior to the closing of its other contacts, relay 250 completes the locking circuit of the line relay I40. This circuit extending from ground at contacts 254, conductor 28, the chain circuit through the back contacts of the other line relays, contacts I4I, I03 and the lower winding of relay I40 to battery. At contacts 25I, relay 250 completes the circuit for energizing the preselected connect relay 280. This circuit extending by Way of ground at contacts 231, contacts 25I, 216, 216 and the winding of relay 230 to battery. At contacts 252, relay 250 prepares a "kick-01f circuit for shunting the distributor relay 215 to cause it to release in case the linefinder has not located the calling line within the release time of the slow-to-release relay 210. At contacts 253, relay 250 opens the operating circuit of all the line relays. At contacts 255, relay 250 applies a ground potential for marking the tens conductor 24 and the units conductor 22. At contacts 256, relay 250 opens the circuit to the slow to release relay 210.

AS the connect relay 200 closes its contacts, it will be noted that only the tens and units relays energized will be the ones whose circuits are completed by way of the marked conductors 22 and 24. and that the finder unit switching relay 240 will only be energized through contacts such as 28I when the finder start relay 260 (instead of 2556) applies ground at contacts 28!. At contacts 286, relay 280 completes a circuit to the units relay 220. This circuit extending by way of the aforementioned ground and over the marked conductor 22, contacts 286 and the winding of units relay 220 to battery. At contacts 292, relay 230 completes the circuit to the tens relay 200. This circuit extending by way of the previously mentioned ground and over the marked conductor 22, contacts 292 and the winding of tens relay 2% to battery. At contacts 293, relay 280 completes a circuit between conductors 34 and 35 to maintain the finder distributor relay 215 in its operated position. At contacts 294, relay 202 places a shunt across the line conductors 30 and 3!, thereby seizing the associated connector and completing a circuit through the differential relay 300 and line relay 3I0. The tens relay 200 and units relay 220 each operate their respective sets of contacts and thereby extend the calling line through to the associated connector in an obvious manner.

In operating contacts 3| I, line relay completes a circuit to the cut-ofi relay Ilii, which extends by way of ground at contacts 3| I', conduct-or 32, contacts 245, 223, 203, conductor I2 and through the winding of relay I00 to battery. At contacts 3I2, relay 3I0 opens conductors 34 and 35, but they are closed at contacts 293. At contacts (H3, relay 3I0 applies a ground potential to the holding conductor 36 which provides the tens relay 200 and units relay 220 with an obvious locking circuit extending through their respective contacts 208 and 225. At contacts 3I5, relay 3I0 completes a circuit for hold relay 320, which extends by way of ground at contacts 382, contacts 3 I 5 and the winding of relay 320 to battery.

At contacts IOI and I02, cut-off relay I00 further opens the operating circuit of line relay I40. At contacts I03, relay I00 opens the holding circuit for relay I40, allowing it to restore. In restoring contacts I46, relay I40 opens the circuit to start relay 250, which upon restoring opens the circuit to connect relay 280 by way of contacts 25L In restoring contacts 293, relay 280 opens the locking circuit of distributor relay 215. In restoring contacts 219, relay 215 completes an obvious circuit to the reset relay 236. At contacts 238, relay 236 applies ground, through the make-before-break contacts actuated by armatures such as 218 and 218 of all the distributor relays such as 215 and 215, for completing an energizing circuit to all distributor relays corresponding to idle finder switches; thus under normal conditions, idle finders are preselected for subsequent calling lines. For example: considering that the first finder is idle, a circuit may be traced from ground at contacts 238, normally closed contacts controlled by armature 218, over the conductor 34 to the first finder (not shown) through contacts corresponding to contacts 3l2 and 322, back over conductor 35' and through the winding of relay 2'15 to battery for operating distributor relay 215', associated with the first finder, to thereby preselect such finder for use on the next call. Similar distributor relays (not shown) associated with idle finders are operated over similar circuits. It will be evident that distributor relay 215 cannot operate at this time since the first finder is busy and contacts 3I2 and 322 of its associated connector have opened the operating circuit to relay 215. At make contacts 216' relay 215' prepares the circuit to connect relay 280 of the first finder, at make contacts 211' prepares a kickoff circuit for relay 215', at contacts 218 substitutes ground through the associated resistance for holding relay 215 operated when reset relay 236 restores, and at contact 219' opens one point in the chain circuit to rela 236. The operation of any distributor relay opens the chain circuit to restore reset relay 236.

The linefinder tens and units relays 2 3 and 22!] are locked operated during the period that either the line relay 3H1 or the hold relay 32B are energized. As the connect relay 2% has restored and the former energizing circuit for the relays 3! ll and 82B opened, they are maintained energized over the extended closed loop including the calling subscribers station.

The aforementioned kick-oil feature will now be explained more in detail. As previously stated, in the event that the linefinder has failed to find the calling line Within the release time of the slow-to-release relay 2M, this timing feature will function to release the linefinder that failed and select the next idle finder which in turn will attempt to connect with the calling line. In restoring contacts 215, relay 2h! completes the kick-off circuit. At contacts 212, relay 2'") opens the circuit to the start relays 251i and 266. At contacts 213, relay 2'?!) completes the circuit to relay 226, which upon energizing shunts its lower winding at contacts 2253, thereby making relay 228 slow-'to-release. At contacts 2217, relay 225 maintains the "kick-off circuit for an added interval of time-by way of a second path, after the start relay 250 restores. Assuming that the last finder has failed to connect with the calling line, the kick-off circuit may be traced from battery and resistance through contacts 252, contacts 211, 2TH, 211 293 and through the winding of distributor relay 275 to battery, thereby shunting out relay 275.

Since distributor relay 275 has both its terminals connected to the negative pole of battery over the above-traced shunt circuit, relay M5 restores. At contacts 2%, relay 2T5 opens the circuit to the connect relay 23E], which restores. A't make contacts controlled by armature Elli, relay 2'15 opens its own locking circuit, at break contacts controlled by armature 278 prepares its own operating circuit, and at contacts ZlS prepares or completes the circuit for reset relay 236, dependent upon the operated or released conditions of the other distributor relays. Connect relay 28B releases and opens its contacts to release the operated tens and units relays 2 2i? and 220 in the last finder, thereby restoring said last finder.

The release of relay 2w opens the circuit of start relay 256 at contacts 212 and also operates relay 225 at contacts 2'53. Relay 226 closes another point in the kick-oil? shunting circuit at contacts 227 so as to maintain the kick-oi? circuit closed for an interval of time after the start relay 259 restores and opens the original kickoff circuit at contacts 252. At contacts 253, start relay 258 restores the original energizing circuit to line relay MR3 and all other line relays; at contacts 254' opens the locking circuit to the line relays; at contacts 255 removes the marking potential from the tens and units marking conductors; and at contacts 256 closes the circuit for reenergizing relay 21E]. Relay tilt, at contacts 213, opens the circuit to relay 22% which restores after a short interval of time and at contacts 212 recloses the circuit for reenergizing start relay 2%. By this time, sufficient time has elapsed to shunt down distributor relay 2'45 and release the connect relay 280 so that by the time start relay 259 is reenergized, the connect relay associated with the next idle finder is operated over contacts 251 of start relay 25B and operated contacts of the distributor relay associated withsaid next idle finder. The reoperation of start relay 256 also at contacts 255 again applies marking ground through the operated contacts of line relay I40 to mark the tens and units marking conductors so as to operate the corresponding tens and units relays in said next idle finder to complete the conmotion to the calling line in the same manner as previously described.

In case two Or more subscribers should initiate calls simultaneously only one of the line relays is held operated over a chain holding circuit while the other line relays are released. For example, it will be assumed that subscribers A and D originate simultaneous calls and therefore line relays Mil and l'lil are simultaneously operated. Start relays 250 and 26b are operated through contacts and H1. The operation 'of either start relay 250 or 250 grounds conductor 28, with the result that the line relay nearest the grounded conductor 28 is the only relay which looks itself through its lower or holding winding. Since line relay I70 is the first relay in the chain locking circuit, this relay at contacts I'll completes its locking circuit, while at contacts I72 the chain locking circuit to subsequent line relays in the chain is opened. Therefore, when either start relay 258 or 258 at contacts 253 or 25% open, the original energizing circuits for the line relays are opened with the result that only the line relay having completed its locking circuit is the only relay (or relay I10 in this case) maintained in operated position. Relay [40, therefore, is restored so that only the tens marking conductor 23 and the units marking conductor 21 are marked through operated contacts ll'5 and N6 of relay HO.

Calls originated after the operation of either start relay 250 or 260 do not operate their corresponding line relays because the operating circuits for such relays are opened at either contacts 2'53 or 264. Since the line relays are released as soon as the finders connect with the calling lines and operate the corresponding cut-off relays, the start relays re only held operated for a short interval of time with the result that subsequent calls can be completed one after the other in rapid succession.

Having described. the invention, what is considered new and desired to have protected by Letters Patent will be pointed out in the appended claims.

What is claimed is:

1. In a telephonesystem, lines having tens and units digit designations, a line circuit for each line including a line relay, an allotter common to said lines, a first and a second start relay included in said allotter, said first relay common to all said lines whose last digit ends in one through five and said second start relay common toall lines whose last digit ends in six through zero, said lines being arranged into tens line groups, a plurality of marking conductors, said marking conductors being divided into two groups, one group being tens marking conductors and the other group being units marking conductors, each tens marking conductor being individual to a corresponding said tens line group, and each units marking conductor being individual to the lines in all said tens line groups having corresponding units digit number designations, a plurality of linefinders, means responsive to the initiation of a call on one of said lines for operating the corresponding line relay, means responsive to the operation of said line relay for selecting said marking conductors corresponding to said calling line and for operating said start relay common to said calling line, means responsive to the operation of said start relay for operating one of said linefinders and for marking said selected marking conductors, and tens and units relays in said one finder operated in response to said marked marking conductors for extending said initiated call.

2. In a telephone system, lines having tens and units digit designations, a line circuit for each line including a line relay, a first and a second start relay, said first relay common to all said lines whose last digit ends in one through five and said second start relay common to all lines whose last digit ends in six through zero, said lines being arranged into tens line groups, a plurality of marking conductors, said marking conductors boing divided into two groups, one group being tens marking conductors and the other group being units marking conductors, each tens marking conductor being individual to a corresponding said tens line group, and each units marking conductor being individual to the lines in all said tens line group having corresponding units digit number designations, means responsive to the initiation of a call on one of said lines for operating the corresponding line relay, means responsive to the operation of said line relay for selecting said marking conductors individual to said calling line and for operating said start relay common to said calling line, and means responsive to the operation of said start relay for marking said selected marking conductors.

3. In a telephone system, lines having tens and units digit designations, a line circuit for each line including a line relay, an allotter common to said lines, a first and a second start relay included in said allotter, said first start relay common to all of said lines whose last digit ends in one through fiive and said second start relay common to all of said lines whose last digit ends in six through zero, means responsive to the initiation of a call on one of said lines for operating the corresponding line relay, means responsive to the operation of said line relay for operating said start relay common to said calling line, a plurality of linefinders, and means responsive to the operation of said start relay to operate one of said linefinders for connecting with said calling line.

4. In a telephone system, lines having tens and units digit designations, a line circuit for each line including a line relay, an allotter common to said lines, a first and a second start relay included in said allotter, said first start relay common to all of said lines whose last digit ends in one through five and said second start relay common to all of said lines whose last digit ends in six through zero, means responsive to the initiation of a call on one of said lines for operating the corresponding line relay, and means responsive to the operation of said line relay for operating said start relay common to said calling line.

5. In a telephone system, lines, a line circuit for each line including a line relay, each of said line relays having a first and a second winding, said first winding providing an operating circuit and said second winding providing a holding cir cuit for said relays, a chain circuit controllable by all of said line relays, means responsive to the initiation of a call on one of said lines for operating the corresponding line relay over its said first winding, and means responsive to the operation of said line relay for serially including said second winding of said relay in said chain circuit to maintain said relay operated only in case no other of said line relays are operated.

6. In a telephone system, groups of subscriber lines having tens number designations corresponding to said groups and units number designations corresponding to the location of said lines in said groups, finder switches having tens and units relays for connecting said finders to calling ones of said lines, a line relay individual to each of said lines, means for operating one of said line relays in response to the initiation of a call on one of said lines, tens and units marking conductors, contacts on said one operated relay for marking one of said tens marking conductors corresponding to the tens number designation of said calling line and for marking one of said units conductors corresponding to the units number designation of said calling line, a connect relay individual to one of said finders operated in response to the operation of said line relay, contacts on said operated connect relay for extending the markings on said marked tens and units marking conductors to operate the corresponding tens and units relays in said one finder to complete a connection from said calling line to said one finder, means for releasing said operated line relay in response to the connection of said one finder to said calling line, and means for preventing the operation of a second one of said line relays during the time a preceding one of said line relays is operated.

7. In a telephone system, a plurality of subscriber lines, a line relay individual to each line, a finder switch having access to said lines for completing outgoing calls from said lines, tens and units marking conductors marked in response to the operation of a line relay of a calling one of said lines, tens and units relays in said finder operated over said marked conductors for operating said finder to connect with said calling line, and means including a chain circuit extending through contacts on said line relays in series for preventing simultaneous markings of said marking conductors by two or more of said line relays in case two or more of said line relays are simultaneously operated responsive to the initiation of simultaneous outgoing calls from two or more lines.

8. In a telephone system, a plurality of subscriber lines, a line relay individual to each line, a finder switch having access to said lines for completing outgoing calls from said lines, a plurality of circuits closed by the operation of a line relay of a calling one of said lines for operating said finder switch to connect with said calling line, and means including series of contacts on all said line relays arranged in a chain so that when a plurality of line relays are operated only one will be maintained operated to close said circuits to said finder switch.

9. In a telephone system, a plurality of subscriber lines, a line relay individual to each line, a plurality of finders having access to said lines for completing outgoing calls from said lines, means including automatic switching apparatus for preselecting an idle one of said finders, a plurality of circuits closed by the operation of a line relay of a calling one of said lines for operating said preselected finder to connect with said calling line, and means includin series of contacts on all said line relays arranged in a chain so that when a plurality of line relays are operated only one will be maintained operated to close said circuits to said preselected finder.

10. In a telephone system, a plurality of lines,

9 a line relay individual to each line, a plurality oi finder-connector links, tens and units relays in the finder portions of said links for connecting calling ones of said lines to the associated connector portions of said link, means for preselecting an idle one of said finder-connector links for use, means efiective when a call is initiated over one of said lines for operating the corresponding one of said line relays, a certain tens relay and a certain units relay in said preselected finder connector link operated in response to the operation of said one line relay for connecting said calling line through said finder portion to said connector portion of said preselected link, means for releasing said one line relay in response to the extension of said calling line to said connector portion of said preselected finder-connector link, and means for preventing the operation of any other line relays after said one line relay has been operated, until after said one line relay has been released.

11. In a telephone system, a plurality of lines, a line relay individual to each line, a finder terminating a trunk, tens and units relays in said finder for connecting calling ones of said lines to said finder, means efiective when a call is initiated over one of said lines for operating the corresponding one and of said line relays, a certain tens relay and a certain units relay in said finder operated in response to the operation of said one line relay for connecting said calling line through said finder to said trunk, means for releasing said one line relay responsive to said connection of said calling line to said trunk, and means for preventing the operation of any other line relays after said one line relay has been operated, until after said calling line is connected through said finder to said trimk and said one line relay has been released.

12. In a telephone system, a plurality of lines, a line relay individual to each line, a start relay common to said lines, normally closed contacts on said start relay, normally open contacts on said start relay, an individual operating circuit including the line conductors of said line and said normally closed contacts on said common start relay for each of said line relays, means for operatin any one of said line relays over its individual operating circuit, normally open contacts on each of said line relays for operating said common start relay in response to the operation of any one of said line relays, and a holding circuit for each line relay including a locking contact on each line relay and said normally open contacts on said common start relay.

13. In a telephone system, a plurality of lines, a line relay individual to each line, a start relay common to said lines, normally closed contacts on said start relay, normally open contacts on said start relay, an individual operating circuit including the line conductors of said line and said normally closed contacts on said common start relay for each of said line relays, means for operating any one of said line relays over its individual operating circuit, normally open contacts on each of said line relays for operating said common start relay in response to the operation of any one of said line relays, and a holding circuit including said normally open contacts on said common start relay and a chain circuit progressively extending through contacts on said line relays in series for maintaining only one of said line relays in operated position at a time.

ROY W. JONES.

No references cited. 

